This application relates to magnetic disc drives and more particularly to low cost base plates having over-molded structural components and to a method for forming low cost base plates having over-molded structural components.
Disc drives are data storage devices that store digital data in magnetic form on a rotating storage medium on a disc. Disc drives have an outer framework that includes a base plate and top cover. The base plate is essentially a platform to which disc drive components are secured and is of a size and shape to mount the disc drive to the chassis of the computer. The top cover of the disc drive cooperates with the base plate to form an internal sealed compartment for housing other components of the disc drive.
Typically, the base plate is composed of aluminum or steel and is formed through either a metal die-casting or extrusion process. Die-casting the base plate is well-known in the disc drive art, involving the addition of molten aluminum or steel, forced under pressure, into a mold conforming to the appropriate size and shape of a disc drive base plate. Once formed, the plate undergoes post machining operations to reach required industry size tolerances. The base plate is then e-coated to remove silicon-based agents used in the die casting process and seal the porous die cast metal. Finally, numerous pre-fabricated and inventoried components of the disc drive are installed onto the base plate. These components include but are not limited to the filter bracket, crash-stops, latching devices, mounting bosses, sound attenuation devices and shock protection features.
Forming a base plate by extrusion entails that the aluminum or steel substrate be extruded through a base plate shaped die. Extrusion, like die-casting, requires costly post machining operations to bring the base plate within industry sizing tolerances, and also requires the installation of the pre-fabricated inventoried components to the base plate. Extrusion, however, unlike die-casting, does not require the e-coating step and is, therefore, typically considered the preferred method for forming the base plate.
The die-casting and extrusion techniques for forming the base plate require that pre-fabricated disc drive components be installed onto the machined base plate. The components are manufactured separately from each other and are assembled onto the base plate using various forms of fastening techniques, such by screws, nuts, clips or press fits. The process of installing the pre-fabricated components onto the base plate is costly and time consuming for the following reasons: (1) each pre-fabricated component part, feature or assembly requires its own manufacturing cost attributed to materials, labor, energy and shipping resources; (2) each pre-fabricated component incorporates tightly toleranced location features for locating the component to the base plate, where the location features are designed for and maintained through costly quality control programs; (3) each individual pre-fabricated component is inventoried, tracked, inspected and stored for the base plate manufacturing process; (4) each fastening technique used to fasten a pre-fabricated component to the base plate has its own cost attributed to material and labor; and (5) each fastening technique requires that pre-fabricated components be secured to the base plate in an ordered fashion, i.e., require costly xe2x80x9cbalanced manufacturing linesxe2x80x9d that incorporate additional work stations and workers.
Accordingly, a need exists in the art to minimize expenses of, and time lost during, the manufacture of conventional disc drive base plates.
Against this backdrop the present invention has been developed. The present invention is a low cost disc drive base plate having a platform portion and at least one structural component of the disc drive over-molded to the platform portion.
In accordance with one embodiment of the present invention, the low cost base plate for the disc drive includes a platform portion having a top surface and bottom surface. A disc drive structural component is over-molded onto the platform portion to secure the structural component to the platform portion.
The present invention may also be implemented as a base plate including the platform portion with two or more over-molded structural components. The structural components may be over-molded to either the top or bottom surface of the platform portion.
The present invention can further be implemented as a method for manufacturing a low cost base plate for use in a disc drive. The method typically has the steps of forming a platform portion of the base plate and then over-molding a preferably plastic disc drive structural component to the platform portion so as to fasten the structural component to the platform portion.